SELECTED-ION FLOW DRIFT-TUBE STUDY OF THE FORMATION AND DISSOCIATION OF CO-2 IONS IN NITROGEN BUFFER GAS - THE CO+.N-2 BOND-ENERGY(.N)

Efficient vibrational quenching of CO+ (v = 1) by N-2 led to the deduc tion of an unexpectedly strong attractive potential between CO+ and N- 2. This was subsequently confirmed by ab initio quantal calculations o f the CO+. N-2 bond strength. The bond energy of CO+. N-2 has now been determined in a selected ion flow drift tube, by measuring collisiona l destruction and formation of CO+. N-2. The bond energy is found to b e 0.7 +/- 0.2 eV. This is sufficiently large to rationalize the fast v ibrational quenching but somewhat less than an ab initio value. The la rge value of D(CO+. N-2) can unambiguously be explained by resonance i nteraction between CO+. N, and the charge-transfer CO . N-2(+) states. (C) 1998 Elsevier Science B.V.